viewing rendered animation from command line
Call the operator

To Play Rendered Animation you call the operator. For example sake saved to a file scripts/playback.py

import bpy
bpy.ops.render.play_rendered_anim()


To call the operator from command line

blender -P scripts/playback.py tests/demo.blend


The operator makes a command based on your User Preferences &gt; Files &gt; Animation Player  settings.


Which in the case for Internal Player will be something like

Executing command:
   '/../bin/blender -a -f 24 1.0 -s 0 -e 4 -j 1 /tmp/0000.png'


see blender command line arguments

The script that generates the command can be found in 2.79/scripts/startup/bl_operators/screen_play_rendered_anim.py